The invention relates to a device for dressing a card clothing, especially an all-steel sawtooth clothing, drawn over a cylindrical drum, with a dressing system that can be moved along a path predetermined by a guide element. At least one element of the dressing system can be advanced in a direction that runs transversely, especially perpendicularly, to the predetermined path.
In the processing of textile fibers, the fibers are straightened and cleaned with the use of cards or carding machines. These carding machines comprise a cylindrical drum, whose outer cylindrical surface is covered with card clothing. The carding operation is carried out by rotating the cylindrical drum about its cylinder axis. The clothing mounted on the cylindrical surface runs through the fiber material and straightens it, possibly in interaction with other processing elements, such as card flats, helical rollers, and the like. In addition, this carding also cleans the raw material. The carding clothing may be realized in the form of so-called needle clothing, in which individual needles penetrate an elastic support material. In many cases, of course, a so-called all-steel sawtooth clothing is used to increase wear resistance and to improve the quality of the textile fiber material. A clothing of this type comprises a sawtooth wire, which runs helically around the cylindrical drum and whose sawteeth run through the fiber material.
During the operation of the wires described above, considerable wear of the card clothing occurs. In addition, the clothing can become fouled. The latter problem occurs especially in the processing of synthetic fibers, during which the fibers melt and can adhere to the clothing. Therefore, to maintain the desired quality of the fiber material, it is necessary to dress the card clothing on a regular basis and, in the course of this dressing, to regrind the clothing tips and/or to remove fouling from the clothing.
A suitable device of the type described above for regrinding card clothing is specified, for example, in U.S. Pat. No. 5,797,788. This device comprises a dressing element realized as a grinding stone, which is mounted on a slide of the dressing system. This slide can be moved along a guide element that is realized as a guide rail. In this regard, the device is usually mounted so that the guide rail is approximately parallel to the cylinder axis of the drum that supports the clothing to be dressed. In addition, the dressing element in the previously known device can be moved against the pretensioning force of a spring in a direction that runs perpendicularly to the predetermined path. During the operation of the previously known device, the guide rail is mounted on a machine frame of the card or carding machine and then aligned by means of suitable adjusting mechanisms in such a way that the grinding stone assumes the desired working position. The grinding stone is then pulled away from the clothing against the pretensioning force of the pretensioning device by means of an actuating element mounted on it. The clothing is then set in rotation, the actuating element is released, and the grinding stone is pressed against the clothing by the force of the pretensioning device. In the further course of the dressing operation, the grinding stone is moved back and forth over the entire length of the cylindrical drum parallel to the cylinder axis, until the desired grinding result is obtained.
In a device of a similar design that is described in DE 199 32 679 C1, a cleaning effect is achieved by means of a cleaning blade that can be inserted in the clothing channels. In this regard, the cleaning blade is also forced towards the bottom of the channels by a pretensioning device. Of course, in the case of the device described in DE 199 32 679 C1, it is not necessary for the dressing element realized as a cleaning blade to be moved back and forth by means of an additional drive element, because the cleaning blade is automatically moved along the cylinder axis of the drum by the clothing, which is helically arranged on the cylindrical drum.
Although the devices described above produce satisfactory grinding and cleaning results, it has been found that the maintenance work carried out with these devices is very time-consuming. This results in considerable downtime of the fiber processing equipment and thus high costs related to lost production.